* {
    box-sizing: border-box;
}
body {
    background-color: #f1f1f1;
}
.timeline {
    position: relative;
    max-width: 800px;
    margin: 0 auto;
    padding-top: 20px;
    background-color: inherit;
}
.timeline:after {
    content: '';
    position: absolute;
    width: 5px;
    background-color: #0065b3;
    left: 50%;
    top: 0;
    bottom: 0;
    margin-left: -2px;
}
.timeline--first:after {
    top: 20px;
}
.era {
    text-align: center;
    position: relative;
    z-index: 1;
    padding-bottom: 20px;
}
.era__title {
    background-color: #0065b3;
    color: #fff;
    display: inline-block;
    padding: 10px 20px;
}
.entry {
    padding: 10px 30px 40px 30px;
    width: 50%;
    position: relative;
    background-color: inherit;
}
.entry--right {
    margin-left: 50%;
}
.entry__content {
    padding: 20px 30px;
    background-color: #f9f9f9;
    position: relative;
}
.entry:before {
    content: " ";
    height: 0;
    position: absolute;
    top: 20px;
    width: 0;
    z-index: 1;
}
.entry--left:before {
    right: 22px;
    border: medium solid transparent;
    border-width: 8px 0 8px 8px;
    border-color: transparent transparent transparent white;
}
.entry--right:before {
    left: 22px;
    margin-left: 0;
    border: medium solid transparent;
    border-width: 8px 8px 8px 0;
    border-color: transparent white transparent transparent;
}
.entry:after {
    content: '';
    position: absolute;
    width: 30px;
    height: 30px;
    right: -19.75px;
    background-color: white;
    border: 4px solid #0065b3;
    top: 10px;
    border-radius: 50%;
    z-index: 1;
}
.entry--right:after {
    right: auto;
    left: -18.75px;
}
h2 {
    margin-bottom: 0.5em;
    font-family: sans-serif;
    font-size: 1.2em;
}
p {
    font-family: sans-serif;
    line-height: 1.4;
}
@media all and (max-width: 500px) {
    .timeline:after {
        left: 33.75px;
    }
    .era {
        text-align: left;
        padding-left: 31.875px;
    }
    .entry {
        width: 100%;
        margin-left: 0;
        padding-left: 64px;
        padding-right: 20px;
    }
    .entry:before {
        right: auto;
        left: 56px;
        margin-left: 0;
        border: medium solid transparent;
        border-width: 8px 8px 8px 0;
        border-color: transparent white transparent transparent;
    }
    .entry:after {
        left: 15px;
    }
}